Aotus lemurinus I.Geoffroy Saint-Hilaire, 1843

Activity Pattern

Like other members of its genus, Aotus lemurinus is a nocturnal species.

Head Appearance

It has a small, round head striped with black, dominated by two large brown eyes, giving it an appearance very similar to an owl. When light reflects off its eyes, they shine a reddish orange.

Facial Markings

It has bushy white eyebrows, with a patch of darker fur between them.

Body Fur Coloration

Its overall grey fur is dense and woolly, while the underside of its body ranges from yellow to orange in colour.

Tail Characteristics

Its non-prehensile tail varies in colour from brownish black to orange, and is always tipped with black.

Limb Structure

This species, the gray-bellied night monkey, has slender limbs with long, delicate fingers and wide fingertip pads.

Size and Sexual Dimorphism

Adult individuals can reach a weight of 1.3 kilograms, and no sexual dimorphism has been observed in this species.

Habitat Types

The gray-bellied night monkey occurs in both dry and moist habitats, and occupies all levels of the forest canopy.

Habitat Preferences

It is very rarely found on the ground, and prefers dense vegetation with tangled vines where trees are evenly dispersed.

Geographic Range

Its geographic range extends from Colombia to Venezuela, Ecuador, and Panama, and it is also found in the tropical Andes.

Diurnal Roosting Behavior

During the day, this monkey sleeps in tree cavities or dense thickets.

Foraging Timing

At night, it forages through the canopy for a variety of food items.

Diet Composition

It is primarily a frugivore, meaning it eats mostly fruit, but will also consume vegetation, insects, nectar, and even other small mammals and birds when fruit is not abundant.

Peak Activity Periods

The gray-bellied night monkey is most active during twilight hours and periods of bright moonlight.

Troop Structure

Troops of this species consist of a mated pair and their offspring, with a maximum total of five individuals.

Mating System

This species is known for forming monogamous pair bonds, and parental duties are shared between the breeding pair and juveniles in the troop.

Parental Care Roles

However, the male carries out most caregiving and rearing work; the female only provides nursing for infants. Remarkably, even if the male dies, the female will not take over his parental responsibilities.

Vocalization Characteristics

This monkey is characteristically loud, and produces a wide range of calls. These range from soft clicks and low-pitched guttural rumblings to owl-like hoots, and high-pitched shrieks when it feels threatened.

Resting Behavior

When it is not feeding, the gray-bellied night monkey is typically inactive.

Territory Size

Like other species in its genus, it claims a relatively small territory of around 0.1 km².

Scent Communication

Scent is a key part of intraspecies communication for this monkey; it marks territories with brown, oily secretions from the base of its tail.

Birth Seasonality

Births peak at the end of the dry season and during the middle of the wet season.

Gestation Details

Average gestation length is 133 days, and gestation usually produces a single infant; twins are very rare.

Reproductive Frequency

This species produces only one litter per year.

Sexual Maturity Age

Offspring reach sexual maturity between 2.5 and 3.5 years of age.

Dispersal Behavior

Once mature, offspring disperse, leaving their natal troop to search for an unpaired mate.